1. Field of the Invention
The present invention relates to a pharmaceutical solid preparation containing a poorly soluble drug for the purpose of improvement of dissolution and a process for the production thereof, and more particularly, to the pharmaceutical solid preparation obtained by delivering and discharging/spraying an aqueous solution and/or a water dispersion of a water soluble polymer as well as a plasticizer solution wherein a poorly soluble drug is dissolved, from nozzle outlets simultaneously and separately, and the process for the production thereof.
2. Description of the Invention
In light of efficiency and safety, it has been regarded as important that significantly high bioavailability is set in the designs for pharmaceutical solid preparations. One of important factors which affect bioavailability of medicines includes solubility of drugs, and numerous studies have been carried out regarding the relationship of solubility and digestive tract absorption. In particular, it has been known that the dissolution behavior of a poorly soluble drug is a key determinant of its oral bioavailability. Various methods have been studied for formulation techniques of solubility improvement in poorly soluble drugs, and among them, a solid dispersion element method has shown promise. This method is defined as a method in which a single molecular drug is dispersed in an inert carrier of a drug in a solid state. Several methods have been proposed for the process of production, and especially, a solvent method and a mixed pulverization method are included as practical methods.
The solvent method is a method for producing a solid dispersion by dissolving a drug and a water-soluble polymer which is a carrier in a solvent such as an organic solvent, and subsequently distilling off the solvent, or by dissolving the drug in the solvent, dispersing in the carrier followed by distilling off the solvent. It is believed that solubility and bioavailability can be improved because the drug becomes amorphous by dissolving the poorly soluble drug in the solvent and is dispersed in the carrier in such a state.
As specific examples of the solvent method, Japanese Patent Publication (JP-B) Nos. 3-1288/1991 and 3-28404/1991 have reported that the solid dispersion is obtained as follows. Lactose or the like is granulated with a water-soluble polymer such as hydroxypropylcellulose to make fine particles. Nifedipine which is a poorly soluble drug and a polymer base such as poly(vinylpyrrolidone), hydroxypropylmethylcellulose and methylcellulose are dissolved in the organic solvent to form a solution. The solution was sprayed on the fine particles. The sprayed particles are dried to yield the solid dispersion. Also, in Japanese Patent Provisional Publication (JP-A) No. 281561/2000, the solid dispersion is prepared by dissolving a poorly soluble drug such as cycloheptadines and the water-soluble polymer such as poly(vinylpyrrolidone), hydroxypropylmethylcellulose and hydroxypropylcellulose in a water/alcohol system, and subsequently spraying on lactose followed by granulating.